Mark Sin Seok-bok, originally from Myeongrye in Miryang, Gyeongsang-do (now, Myeongrye-ri, Miryang-eup, Gyeongnam), was a merchant. He was arrested by the police of Daegu with other believers including James Oh during the Byeongin Persecution in 1866. He was on his way home from Mapo, Changwon where he went for business. He practiced the Catholic religion for over 10 years.

The arrest of Mark Sin was premeditated, as the police of Daegu were informed that he was a Catholic. The police invaded the Myeongrye village and found his home, and took all his fortune. By tracing the rumors, the invaders found out that Mark Sin had gone out of town for business and would be on his way home. They ran to the place where Mark Sin would probably pass by, and met him in Gasan, Gimhae. They confirmed that he was a Catholic and arrested him, and sent him into custody in Miryang.

His captors treated Mark Sin mercilessly during their one-day stay in Miryang, then, took him to Daegu. Mark Sin‘s brothers who learned what happened to their brother prepared some money and ran after them. They made a deal with the captors to release their brother. But Mark Sin asked his brothers `not to give them even a penny.` Because of that Mark Sin enraged the police all the more.

In Daegu, he had to go through more severe punishment. He was bleeding and all his bones were broken. He never renounced his religion, but kept replying; "Even if you release me, I will continue to believe in God."
The chief official who was very angry at him, ordered that Mark Sin be tortured more cruelly, and put him in prison. A few days later he was hanged and died a martyr. It was on March 31, 1866 (February 15, by the Lunar calendar). Mark Sin was 38 years old.

Mark Sin`s family came to take his body and buried it in his hometown.